Methods of counterbalancing hight adjustable work surface with constant force springs

ABSTRACT

Constant force springs are implemented to counterbalance adjustable height work surfaces cooperating with a substructure that further cooperates with open linear extension mechanisms and position retention mechanisms further cooperating with one or more bases. The methods include direct connecting the springs, and connecting the springs to one or more chains looping over one or more sprockets, the chains then connected to the substructure where methods to control the spring ends, and to address imbalances in the spring forces are included.

NOTE

This application claims priority to U.S. 62/230,883

BACKGROUND

Counterbalancing an adjustable height work surface using a long large diameter torsion spring was a commercial success decades ago in a drafting table, and has since seen many refinements to the technique.

This did not expand into other applications significantly, and the advent of computer aided design fairly quickly replaced the drafting table. This was followed by efforts focused on ergonomic adjustments in the 1980's and '90's. Adjustable height tables have various niche applications where the refined torsion spring counterbalancing saw competition from units with motorized lead screw drives linked to motion control circuitry and software, and very capable of movement with variable loads.

With the release of some medical research in recent years there is some justification for a much broader adoption of sitting to standing adjustable height work surfaces.

While motorized units have come down in price I believe there are applications that would welcome less costly counterbalanced units described herein. They require position retention mechanisms which are normally engaged; easily user disengaged, and can withstand considerable loads.

One or more methods described herein could be used with inverted telescopic mechanisms and other open linear extension mechanisms, however, the methods herein show work surface substructures cooperating with open linear extension mechanisms, preferably mass produced drawer slides or slides, which appear to offer a lower cost approach enabling the potential health benefits to reach more people.

SUMMARY

While motorized lifting has advantages, there are inherent costs that may be avoided by utilizing constant force springs to counterbalance the work surface and substructure that cooperates with known position retention methods that are normally engaged, and easily disengaged by one or both hands when changing the height. Social norms are leaning towards a healthy lifestyle, and low carbon footprints, where no motor may be an advantage.

Benefits

There is a serious health reason for some, and a healthy reason for many to be using an adjustable height work surface that won't see wide adoption until products reach affordable levels.

Counterbalancing with larger constant force springs is a light weight and relatively compact approach, and will last for 25,000 cycles.

There are few moving parts and basically no electrical parts which improves reliability.

Broad application potential, as the methods herein are compatible with movable and mobile configurations as well as desk, free standing, and wall mounted configurations.

Fully functional in applications and locations where electricity may not be available or reliable.

Limitations

The methods herein are limited to the implementations of constant force springs described as CF springs to provide a counterbalancing force equal to the weight of suitably equipped work surface and its cooperating elevated substructure enabling the user to easily and quickly manipulate its height.

CF springs offer fixed forces, where auto-adjustable force methods, and motorized lifting capabilities have distinct advantages in some applications.

To mitigate this limitation and better accommodate users, a stronger spring force is typically provided with the means to add ballast to counterbalance just the work surface, where the user can add preferred objects to the work surface and substructure, and remove ballast to re-balance.

The user can also further upgrade the CF springs that are easy to replace. However, even with these capabilities, applications requiring frequent load adjustability would not be applicable.

There is a risk of Overloading a work surface and then releasing its position retention system. A safety measure of providing 2 release mechanisms requiring the user to place both hands in a positions to hold the work surface is one option. Electrical circuits that sense overloads and lock the release mechanism are also known.

DESCRIPTION OF DRAWINGS

1. FIG. 1. Right rear ISO view of CF springs rotationally cooperating with the upper extents of base objects, and the extended CF spring directly cooperating with a substructure of an asymmetric work surface.

2. FIG. 2. A left rear view of CF springs rotationally cooperating with the lower extents of the substructure, and the extended CF spring directly cooperating with the stationary base objects of an asymmetric work surface.

3. FIG. 2A is a close up of substructure mounted springs.

4. FIG. 3. A left rear view of the CF springs rotationally cooperating with the lower extents of the base objects, the extended CF springs cooperating through a coupling with flexible roller chain that cooperates with the substructure of an asymmetric work surface.

5. FIGS. 3a, 3b are close-ups of exemplary method of constraining the coupling to a flexible object.

6. FIG. 4 An opposed pair of CF springs cooperating with the lower extents of the base objects, and further cooperating with a roller chain that cooperates with the substructure.

7. FIGS. 4a, 4b are close-up views of upper connection to the chain, and the lower chain connection to the substructure.

8. FIG. 4c Additional components to support the opposed pair springs.

9. FIG. 5 The design of FIG. 4 with added coupling orientation guides, a preferred method to address unequal force opposed pair CF springs.

10. FIG. 5a is a close up of the guided coupling, chain and sprocket.

11. FIG. 6. is a rt. rear view of CF springs cooperating with a symmetric or free standing work surface substructure comprising spaced apart sub-assemblies cooperating through slides with base objects. A torsionally rigid shaft provides self-leveling.

12. FIG. 6a is a close up cutaway view of an exemplary removable CF spring installed in a base object.

13. FIG. 6b is an elevated Rt. Side view through the work surface for close up view 6 c.

14. FIG. 6c is a close up of cooperating objects connecting the CF spring to the substructure sub-assemblies on the right side of the sprocket.

15. FIG. 6d . identifies an inner structural support.

DETAILED DESCRIPTION

While methods to incorporate constant force or CF spring counterbalancing within closed telescopic mechanism designs is possible, the methods herein are applicable to open linear extension mechanisms where the lower extents of the substructure is accessible at all elevations, and the springs are cooperating with a substructures in different locations not available or practical in some other substructures. However, by inverting the telescopic components, where the lower extents of the substructure is accessible does offer opportunities not covered herein. Some of the linear mechanisms cooperating with torsion spring lift assistance could also be adapted to the methods herein.

The applications described herein are associated with a substructure cooperating with drawer slides or open linear extension mechanisms described as slides, but this should not be construed as limiting the scope of this description.

Providing ways a user can compensate for a change in load is a desirable capability. This is accomplished by providing a greater counterbalancing force that cooperates with one or more containers of ballast that cooperate with the substructure or work surface to achieve counterbalance. This enables the user to add objects to the work surface and subtract ballast from the containers to regain desired counter balance. The user can also add additional CF springs to some substructures, and or swap these CF springs for higher force CF springs in all substructures.

Each CF spring is constructed from thin sheet stainless steel in a range of thicknesses, and further formed and annealed into a coil spring in various diameters and widths. Smaller diameters of the same thickness provide higher forces but shorter life. Each CF spring coil has a free end that will extend out on a predictable larger radius for one quarter of a turn, and can then continue tangentially at that point on a linear path if the free end is constrained flat in the plane of travel. A distance of 1 diameter to preload the recoiling force is recommended. Higher forces are achievable by winding two or more coils on the same hub. Two or more hubs can work in parallel or as an opposing pair with one another. An opposing pair provides a method to neutralize end torsional deformation that each coil produces by positioning them to oppose one another. This is cost effective when connecting to a flexible object like roller chain, and the CF spring forces are matched. This is accomplished by aligning the free ends to extend together by connecting each opposing spring free end to one coupling causing these torsional forces to cancel each other.

This free end torsional deformation causes deformation of the extended length of the spring if the free end features were simply connected to a chain, or other suitably flexible object where preferably a CF spring to chain coupling further cooperates with guides over its linear travel, the guides cooperating with the base manipulate the coupling by restraining it to a vertical orientation throughout its linear travel. An exemplary method of guiding the coupling is provided herein where methods requiring fewer components would be preferred.

The first five implementations are illustrated on the back sides of an asymmetric work surface substructure where only the visible substructure back and side objects are identified. Utilizing CF springs for counterbalancing in other substructures only requires access to the lower extents of the movable substructure objects.

The sixth implementation is a with symmetric work surface cooperating with 2 substructure sub-assemblies further cooperating with slides and 2 base structures. They are all preferred designs and depend on applications, anticipated loads, and other considerations. Connecting the free end of the CF springs directly to the substructure in the first two implementations are preferred for fewer parts and lower cost.

A second method is connecting a flexible material, preferably roller chain to the CF spring that loops over a hub or sprocket to reverse the direction of the flexible material then connected to the lower extents of a substructure. Although more costly, its added benefit using chain with aligned and connected sprockets may be worth the expense.

The opposed pair CF spring orientation is a third method that has an advantage of canceling the free end torsional forces with matched springs.

The width of the substructure limits the number of CF spring coils that could be added to the first 2 methods assuming all other components are structurally capable.

Single chain and sprocket designs with the opposed CF springs are examples where using belting or chord or other flexible material to substitute for the roller chain may present additional cost savings.

However, aligned sprockets and chain designs of FIGS. 3,6 enable the potential benefit of distributing imbalanced applied forces coming from either the CF springs or an imbalanced work surface load. To achieve this potential, an object or shaft connecting sprockets exhibits minimal torsional distortion to maintain sprocket alignment resulting in equal linear movement of the one or more substructures. This enables CF spring designs to utilize imbalanced CF spring loads without adverse consequences.

Referring to FIG. 1, the substructure panel 13 cooperates with vertical objects 11,12 that further cooperate with drawer slides 30 that further cooperate with base objects 41,42 representing wall mounted, mobile chassis, or stationary base objects where additional structural base objects are not shown. A cross member 43 cooperates with the base objects 41,42 and further cooperates with one or more brackets 44 that further cooperate with one or more shafts 61 that rotationally cooperate with hubs 62 further comprising one or more parallel CF springs 63.

Bracket 44 may further comprise a second pair of shaft retention features 45, that accommodate smaller diameter CF spring coils. All these shaft retention features preferably comprise an otherwise interfering feature that cooperates with slight cuts across the shafts to retain the shafts laterally (not shown). Other methods may be considered.

The extended free ends 64 of the one or more CF springs comprising attachment features cooperate with stud features on bracket 45, further comprising a clamping plate and nuts (not shown) to clamp the end of each spring, bracket 45 further cooperating with the lower extents of the substructure object 13 maintain the spring ends flat in the plane of travel.

When the substructure is lowered to the sitting position as shown, the working extension of the CF springs is dimensionally equal to or greater than the maximum travel distance plus the CF spring preload distance to maintain a counterbalancing force throughout the range of vertical height positions of the substructure cooperating with the work surface 20. This is true for all these implementations, where the travel distance becomes shorter with larger diameter springs but the life cycles increase significantly.

Referring to FIG. 2 the substructure panel 13 cooperates with vertical objects 11,12 that further cooperate with slides 30 that further cooperate with base objects 41,42 representing wall mount base objects as shown, or mobile or stationary chassis mounted base objects where additional structural base objects are not shown. The extended ends 64 of CF springs cooperate with studs connected to brackets 49 that are connected to cross-member 50 cooperating with the base objects 41, 42. An additional feature 48 is a hole that would cooperate with a hand tool for ease of assembly or dis assembly of the preloaded springs and applies to all implementations described herein. Engaging or disengaging the CF springs in all these implementations is accomplished with the substructure fully extended

Referring to FIG. 2a , the lower extents of the substructure are modified to cooperate with brackets 47 further comprising slots 47 a having a slight upward angle that retains one or more preloaded CF spring coils 63 and hubs 62 rotationally cooperating with shafts 61 that slideably engage and are captive within the slots 47 a under load.

Referring to FIG. 3, this implementation has more parts and cost, but also provides a self-leveling and load balancing capability that is maximized by positioning the CF springs and associated components further apart than shown, preferably proximate to the vertical objects 11,12. The substructure panel 13 cooperates with vertical objects 11,12 that further cooperate with drawer slides (not visible) that further cooperate with base objects 41,42 common to all base structures. This example base structure comprises the pillar objects 41,42 that further cooperates with the legs 41 a, 42 a, the added gusset 41 b, and cross members 77, 78, and 51 representing a preferably mobile or stationary chassis base structures. Other base structural components are omitted. The cross member 51 further cooperates with two or more brackets 52 further comprising upwardly angled slots 53 providing retention features that cooperate with one or more parallel shafts 61 that rotationally cooperate with hubs 62 further comprising one or more CF springs 63.

The one or more CF spring extended free ends 64 cooperate with attachment features of the one or more couplings 65 that further cooperates with a clamping plate 76 retained by threaded fasteners.

Referring to FIGS. 3a, 3b , the coupling 65 further comprises two spaced apart preferably pressed in stub shafts 72 on each sidewall cooperating rotationally with small idler wheels 73 that further cooperate with the insides of channel objects 74 that fixedly cooperate with upper and lower sets of bracket objects 75 further cooperating with cross members 77,78.

Couplings 65 further comprise attachment features 79 to cooperate with the first ends of one or more preferred roller chains 66 that loop over one or more sprockets 67 (shown without teeth). The sprockets do have teeth that are aligned and fixedly cooperate with a shaft 68 that rotationally cooperates with bracket 69 further cooperating with cross member 77 further cooperating with the base objects 41,42.

Referring to FIG. 3b , the one or more roller chains loop over the aligned sprockets and extend downward where the second ends of the chains that may utilize master links to cooperate with features 70, cooperating with a bracket 71 that further cooperates with the lower extents of the substructure.

The fixed alignment of the sprockets 67 on the shaft 68 that is highly resistant to torsional loads, allows a stronger CF spring force urging one chain on one sprocket to communicate this greater force through the shaft to all other sprockets enabling dissimilar CF spring forces to act in unison, and eliminates any imbalance in the counterbalanced force applied to the substructure.

When utilizing two or more CF spring coils, they may be positioned near the CG of the substructure as shown, or spaced further apart, preferably equidistant from the CG of the substructure, and preferably as far apart as practical.

This low friction wheels in channels method may be configured on the sides of the springs as shown or on the front or back sides of the CF springs, and where a sliding fit between the coupling and the channel objects (shown in FIG. 6) may be more economical, but would increase friction. The torsional force proximate to the end of the CF spring is quite strong, where increasing the vertical distance between the wheels or sliding points of contact would reduce the stresses.

Other sliding or rolling features cooperating with fixed vertical objects can also be considered. Linear bearings or bushings retained by the coupling 65 cooperating with a vertical shaft would be another implementation.

Referring to FIG. 4, 4 a, 4 b, 4 c the opposed pair of CF spring coils 63 neutralize the residual distortions when the extending ends 64 are fastened together, and cooperating with coupling 65 further comprising a feature 79 to connect the chain 66, and a clamping plate 76 similar to those shown in FIGS. 3b, 4a, 5a . This coupling should not require manipulation by guides as shown in these figures, provided the spring forces are balanced, and just cooperates with the first end of a roller chain 66 that loops over a sprocket 67 and downward to cooperate with object 70 cooperating with bracket 71 as shown in FIG. 4b that further cooperates with the lower extents of the substructure.

The sprocket 67 rotationally cooperates with a shaft 68 that cooperates with bracket 69 further cooperating with cross member 77 further cooperating with the base objects 41,42.

Referring to FIG. 4C, the shafts 61 rotationally supporting each hub cooperating with the one or more CF springs are vertically retained by lower cross members 81,82 comprising pairs of level horizontal slots 83 that enable different size CF springs to be installed. Shaft collars 84 retain the shafts.

Removing a cosmetic and safety panel provides access. Loosening the coupling fastener is recommended, then removing shaft retainers 84 on the rear side and applying firm downward palm pressure to the top of a CF spring coil allows the shaft to be removed toward the front, and releasing the coil slowly enables it to fully recoil. Removing the fasteners and the clamping plate from the coupling 65 enables the spring to be removed and replaced, by simply reversing this removal sequence.

This arrangement is limited to matched pairs of CF springs, which is suitable for many applications.

However, adding the guided coupling as shown in FIGS. 3, 5 addresses the 10% spring force variations that might otherwise require sorting and matching, and the opportunity to mix CF spring force combinations in this product is beneficial.

Referring to FIGS. 5, 5 a, the bracket 69 cooperates with cross member 77 that further comprises an internal opening to accommodate the guided coupling 65 cooperate with clamping plates 76 (shown in FIG. 3b ). The coupling further comprises a feature 79 to cooperate with the chain 66 using a master link preferably.

The stud mounted wheels 73 are shown, but normally cooperating with channel object 74 that further comprise a bracket 75 cooperating with cross member 77. The opposite channel object (not visible) is cooperating with bracket 69. The channel objects 74 further cooperate with lower brackets 75 cooperating with the cross members 81,82.

Referring to FIG. 6, the CF springs counterbalance a symmetric work surface 20 and substructure cooperating with drawer slides, and can further cooperate with removable ballast.

The Work surface cooperates with separated substructures 111, 112 that on their inside facing surfaces, cooperate with a load distributing object 113 shown in FIG. 6C preferred with some semi-rigid material choices for these objects 111,112. The substructures 111,112 further cooperate with slide objects 31, cooperating with slide objects 32, that further cooperates with slide objects 33 that further cooperates with the narrow end surfaces of a base objects 41, 42 that are formed as an open channel shape in a horizontal cross section, and preferably wider at the base as shown. A cutaway of the side of base object 42 exposes the CF spring location. The same view would occur for either side of either base object. These base objects further cooperate rigidly with multi-directional feet (not shown) that would preferably comprise a connection between them along the floor.

Referring to FIG. 6A, The one or more CF springs 63 on each hub 62 rotationally cooperates with a shaft 61 retained in features of two sided bracket 85 that provides a handle 86 on one end and further comprises features 87 to pivotably cooperate with features 96 of the structural brace 88 (shown in FIG. 6d ). An opening in the lower extents of the end surface of the base object 42 is normally covered by a structural cover plate (not shown) securely attached through the array of fastener clearance holes 89 to cooperate with threaded features in the structural brace 88 (shown in FIG. 6d ).

The pivotable bracket arms, or arms 85 are shown in the engaged position where the handle end 86 will further cooperate with one or more engaged latches (not shown) further cooperating with the base objects. Releasing the arm and pivoting it upward about sixty five degrees enables the CF spring to recoil its preload. The arms 85 would cooperate with a latching position retention (not shown).

After removing the cover plate from the base object 42 end surface, and the fasteners retaining the clamping plate 76 to the coupling 65, the free end of the CF spring is disconnected from the coupling.

A previously described hand tool facilitates releasing the CF spring if needed.

The arms 85 further comprise two pivoting shaft retention brackets 93 utilizing gravity to remain normally closed, the brackets: cooperate together, further comprise locking teeth 94, and manual release levers 95. Lifting either of these two pivotally connected levers 95 allows the shaft 61 cooperating with the CF spring 63 to drop nearly straight down. The curved ends of the lower shaft guides manipulate the falling CF spring by redirecting its downward momentum to a horizontal momentum urging the CF spring out the opening.

Replacing the CF spring including the hub and shaft begins with a) insuring the arms 85 are latched up, b) sliding the spring through the opening and with one hand underneath, and c) lifting the spring up 3 inches, where the shaft 61 lifts the locking teeth 94 and gets retained behind these teeth.

If needed, using the previously described small hook ended tool cooperating with feature 48 in the spring as described for FIG. 2, the free end of the CF spring is installed on the studs of the coupling followed by the clamping plate 76 and fasteners. After re-installing the cover plate, the bracket 85 is released and pivoted down to the horizontal position an securely latched in place. This pivoting down uncoils the CF spring to the preloaded condition as shown.

The coupling 65 is guided in channels 74 that extend below their integral mounting bracket 75 features. The bracket 75 features are trimmed to allow access to the chain connection and the removable clamping plate 76.

Referring to FIG. 6b , this elevated side view, identifies the work surface 20, and the two substructures 111,112 cooperating with slide components 31 further cooperating with slide components 32 further cooperating with slide components 33, that cooperate with the base objects 41,42 that further cooperate with multi-directional feet (not shown). The torsionally rigid shaft 166 is also shown.

Referring to FIG. 6c , added bracket 113 cooperates with substructure objects 111, 112 to communicate loads between objects 111,112 and cooperating mounting block 70 that further cooperates with the second ends of the chains 66 that loop over sprockets 67, and continue down to the coupling position shown in FIG. 6a . Object 113 also communicates loads to a position retention mechanism (not shown) located on the opposite side of base 42 from object 70.

Feature 91 is a cutout of the side wall of base object 42 to accommodate the chain and sprocket.

Channel objects 74 with their integral mounting flanges 75 are visible. Other sliding fit or rolling fit guided coupling methods may reduce sliding friction and reduce costs.

The sprocket 67 hides a shaft 68 extension on the far side that is preferably smaller in diameter than shaft 68 shown, and cooperates with a bushing cooperating with base 42.

Shaft 68 is shown to be a large diameter to emphasize the torsional stiffness required to provide minimal torsional deflection between two fixed and radially aligned sprockets over longer distances. The benefit of this known minimal torsional deflection technique is maintaining level motion, and distributing any excess force from one CF spring to both sprockets and both substructure objects, allowing uneven CF springs forces to cooperate without altering the preferred level motion.

This minimal torsional deflection technique is known but not in cooperation with CF springs, or specifically to resolve imbalanced combinations of CF springs for counterbalancing work surfaces.

Referring to FIG. 6d , the braces 88 provides the additional structural support for the opening in the base object 42, and the bracket pivot features 96.

Each brace 88 will comprise features to cooperate with a multi-directional foot to extend stability from the floor to the elevated work surface.

Adding ballast to the asymmetric substructures can be accomplished with one or more containers of sand placed in the lower extents of the preferred substructure, where it is essentially hidden, or cooperating with the back side of object 13 in wall mounted configurations. The symmetric design of FIG. 6, with additional load capability would provide one or more methods to store ballast cooperating with the work surface underside, or the substructure sub-assemblies. 

1. A method of counterbalancing a variable height work surface cooperating with a substructure that cooperates with a plurality of open linear extension mechanisms and position retention mechanisms that further cooperate with one or more base objects, wherein: a one or more CF springs cooperate with one or more hubs rotationally cooperating with one or more shafts are retained by features of the one or more base objects proximate to its upper extents, b the extended free ends of the CF springs cooperate directly with the lower extents of a substructure enabling the CF springs to upwardly urge the substructure and work surface with a counterbalancing force, c the work surface cooperating with a sub-structure may be counterbalanced or preferably further comprise added ballast to attain counterbalance that can be removed as preferred objects are added to the work surface or substructure, d additional shaft retention features for CF springs, and additional CF spring end mounting features on the substructure enable the user to further manipulate counterbalance force.
 2. The method of claim 1 where the arrangement is reversed and shafts cooperating with the one or more hubs with CF springs thereon cooperate with substructure retaining features proximate to its lower extents wherein: a. the retaining features for the shafts slope upward in the substructure retaining the CF springs by their upward urging, b. the free ends of the CF springs cooperate with base object retention features proximate to its upper extents in the plane of travel, enabling the CF springs to upwardly urge the substructure and work surface with a counterbalancing force equal to or preferably greater than needed to elevate the work surface and substructure.
 3. A method of counterbalancing a variable height work surface cooperating with a substructure further cooperating with a plurality of linear extension mechanisms and position retention mechanisms further cooperating with one or more base objects, wherein: a shafts, rotationally cooperating with the one or more hubs with CF springs thereon, are aligned to the X axis and retained in base object brackets at its lower extents, the free ends of the one or more springs extend upward, cooperating with couplings further cooperating with first ends of roller chains that loop over one or more sprockets cooperating with a shaft rotationally cooperating with base object features proximate to its upper extents, the second ends of the one or more chains extending downward and cooperating with the lower extents of the substructure enabling the one or more CF springs to counterbalance the substructure and work surface with a force equal to or preferably greater than needed to elevate the work surface and substructure.
 4. The method of claim 3 where each coupling further comprises features or objects that are vertically separated and cooperate with stationary vertical surfaces that extend the travel distance of the coupling and constrain the movable coupling to retain the vertical orientation of the cooperating CF spring ends by counteracting the torsional force imparted by these springs wherein: a. these vertical surfaces further cooperate with base objects or features for stability, and slideably constrain cooperating surfaces of each coupling that preferably further comprises low friction material in contact areas, b. these vertical surfaces constrain rollers or wheels rotationally cooperating with shafts cooperating with each coupling, enabling a lower friction method to constrain each coupling thereby maintaining the alignment of the cooperating CF spring ends by counteracting the torsional force imparted by these springs.
 5. The method of claim 4 where the plurality of sprockets are fixed in radial alignment to a single shaft that is highly torque resistant enabling sharing of any imbalance between CF spring forces and maintaining the work surface's level orientation during movement.
 6. The method of claim 5 where in a preferred configuration the one or more pair of CF springs and cooperating chains, sprockets and mounting features are spaced as far apart as practical, proximate to the vertical base objects enabling: a. greater counterbalancing forces to be accommodated with less stress and distortion to the base objects and the substructure, b. substantially improved side to side stability of the work surface when it is moving.
 7. A method of providing a constant force counterbalancing of a variable height asymmetric work surface cooperating with a sub-structure cooperating with a plurality of linear extension mechanisms that further cooperate with one or more base objects, wherein: a. shafts, rotationally cooperating with an opposed pair of hubs cooperating with one or more CF springs are retained level in slots in cross members cooperating with the lower extents of the base objects, the free ends of the one or more CF springs extended upward together a preferred distance, cooperate with one coupling and one or two clamping plates, and further cooperating with the first end of roller chain that loops over a sprocket rotationally cooperating with a shaft cooperating with base object features, the second end of the chain cooperating with the lower extents of the substructure enabling the CF springs to counterbalance the substructure and work surface with a force equal to or preferably greater than needed to elevate the work surface and substructure. b. the benefit of the opposed pair orientation where all the spring ends are constrained together is the neutralizing of the torsional forces, provided the spring forces on each hub are equal.
 8. The method of claim 7 where each coupling further comprises features or objects that are vertically separated and cooperate with stationary vertical surfaces that extend the travel distance of the coupling and constrain the movable coupling to retain the vertical orientation of the cooperating CF spring ends by counteracting the torsional force imparted by an imbalance in the pair of opposed springs wherein: a. these vertical surfaces further cooperate with base objects or features for stability, and slideably constrain cooperating surfaces of each coupling that preferably further comprises low friction material in contact areas, b. these vertical surfaces constrain wheels rotationally cooperating with each coupling, enabling a lower friction method to constrain each coupling thereby maintaining the alignment of the cooperating CF spring ends by counteracting the torsional force imparted by said imbalance of spring forces.
 9. The method of claim 5 where a symmetric free standing work surface cooperates with a substructure further comprising two spaced apart sub-assemblies, each cooperating with linear extension mechanisms and position retention mechanisms that cooperate with base objects wherein: a. the base objects further comprise a cover plate covering the access to the CF spring connection and further comprise pivot features to cooperate with the arms of a two sided pivotable bracket that further comprises slot features retaining the shafts cooperating with CF springs, the arms being latch retained in the horizontal working position, b. releasing the latch retaining the two sided bracket and pivoting it upward to a second latching position releases the preload on the CF spring enabling disconnecting of the spring end from a coupling, c. releasing the shaft retaining levers releases the CF spring out of the opening in the base, d. inserting a CF spring with its shaft into the opening and lifting it a few inches will lift and reengage the shaft retaining levers, retaining the spring in position to connect its end to the coupling and install the cover, whereupon releasing the two sided bracket and pivoting it down to its horizontal latched position preloads the CF spring, providing the user a method to change CF springs. 